A soluble form of Siglec-9 provides an antitumor benefit against mammary tumor cells expressing MUC1 in transgenic mice

Yukiko Tomioka, Masami Morimatsu, Ken Ichi Nishijima, Tatsufumi Usui, Sayo Yamamoto, Haruka Suyama, Kinuyo Ozaki, Toshihiro Ito, Etsuro Ono

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Tumor-associated MUC1 binds to Siglec-9, which is expected to mediate tumor cell growth and negative immunomodulation. We hypothesized that a soluble form of Siglec-9 (sSiglec-9) competitively inhibits a binding of MUC1 to its receptor molecules like human Siglec-9, leading to provide antitumor benefit against MUC1-expressing tumor, and generated transgenic mouse lines expressing sSiglec-9 (sSiglec-9 Tg). When mammary tumor cells expressing MUC1 were intraperitoneally transplanted into sSiglec-9 Tg, tumor proliferation was slower with the lower histological malignancy as compared with non-transgenic mice. The sSiglec-9 was detected in the ascites caused by the tumor in the sSiglec-9 Tg, and sSiglec-9 and MUC1 were often colocalized on surfaces of the tumor cells. PCNA immunohistochemistry also revealed the reduced proliferation of the tumor cells in sSiglec-9 Tg. In sSiglec-9 Tg with remarkable suppression of tumor proliferation, MUC1 expressions were tend to be reduced. In the ascites of sSiglec-9 Tg bearing the tumor, T cells were uniformly infiltrated, whereas aggregations of degenerative T cells were often observed in the non-transgenic mice. These results suggest that sSiglec-9 has an antitumor benefit against MUC1-expressing tumor in the transgenic mice, which may avoid the negative immunomodulation and/or suppress tumor-associated MUC1 downstream signal transduction, and subsequent tumor proliferation.

Original languageEnglish
Pages (from-to)532-537
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - Jul 18 2014


All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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